Yield monitor systems are used to measure crop yields during harvesting. Yield characteristics, such as weight or volume, are used to assess the quality and quantity of a crop and accordingly determine its purchase price. In one example a yield equation that assesses the quality and quantity of a crop is based on four distinct variables and a fifth related variable. In one example, the four variables include volume, temperature, moisture and test weight (density) of the harvested crop. The fifth related variable is the weight of the harvested crop, and with at least some yield monitors the weight is determined according to the volume and test weight.
One example of a type of yield monitor is a volume based yield monitor. With volume based yield monitors a volume sensor is provided in a harvester elevator that measures the volume of a harvested crop within the elevator. The operator of the harvester inputs a test weight (density) assumption for the harvested crop in a field based on the observed field conditions, the crop being harvested, as well as the experience of the operator. The weight is derived from the volume measured and the assumed test weight.
Another example of a type of yield monitor is a weight based yield monitor that uses a weight sensor to measure the weight of a harvested crop. With weight based yield monitors the four variables include weight, temperature, moisture and the test weight of the harvested crop. In contrast to the volume based yield monitor, the weight based yield monitor determines the volume of the harvested crop according to the test weight and the weight. Similar to the volume based yield monitor, an operator of the weight based yield monitor assumes a test weight for a field and inputs the assumed test weight. As discussed above, the assumed test weight and the measured weight are used to determine the volume of the harvested crop.